This invention relates to a machine which is used for making slush or ice cream in a freezer, especially in a refrigerator freezer.
Hand cranked ice cream freezers have been known for many years. They usually comprise a metal container in which the ice cream mix is contained, a surrounding vessel holding a freezing mixture (usually ice mixed with salt), "paddles" for stirring the mix, and drive means for the paddles, usually comprising a crank handle and gear train. Laborious hand turning and the need for inconvenient freezing mixtures are the major drawbacks.
Ice cream makers with power driven paddles are known. However, the power requirements are significant. As the ice cream mix progressively freezes, it become increasingly difficult to rotate the paddles in the ice cream. When the freezing process is near completion, rotation is very difficult if not impossible. Where the paddles are motor driven, a relatively powerful motor is required. A clutch was often used to prevent overloading to motor. Such items considerably add to the cost of the machine.
U.S. Pat. No. 2,993,350 to Smith discloses an ice cream maker for use in a refrigerator freezer. A cylindrical container with a stirring blade on its inside wall is rotated about its longitudinal axis. The container contains the ice cream mix. The motor is directly engaged to the container via a gear train. However, to fit the drive mechanism, the container has to be custom made. The dimensions of the container are also fixed. Also, the drive unit has a drive shaft which extends through the wall of the modified container to accomodate the ice cream maker.
What is needed is a machine that employs a new way of agitating the ice cream mix whereby rotating paddle and the like are obviated. The power requirement for agitating the ice cream should be low. Preferably common household containers of various dimensions can be used in place of expensive custom made containers. Safety is of the utmost concern because the machine can be used in the house, where there may be children who may tamper with the machine. The machine should be inexpensive, and its use in the refrigerator should require no modification of the refrigerator.
U.S. patent application Ser. No. 822,377, now U.S. Pat. No. 4,669,274, (which was filed by the inventor of the present invention) has been met the above needs to be used for making slush or ice cream in a freezer. The present invention further provides safety means which prevent the relative movement between the paddle and container when the slush or ice cream has been well formed.